1. Technical Field
The disclosure relates to LED (light emitting diode) bulbs for illumination purpose and, more particularly, relates to an improved LED bulb which can be easily and conveniently assembled, and a method for manufacturing the LED bulb.
2. Description of Related Art
An LED bulb is a type of solid-state lighting that utilizes LEDs as a light source for indoor or outdoor illumination. An LED is a device for transferring electricity to light by using a theory that, if a current is made to flow in a forward direction through a junction region comprising two different semiconductors, electrons and holes are coupled at the junction region to generate a light beam. The LED has an advantage that it is resistant to shock, and has an almost eternal lifetime under a specific condition; thus, the LED bulb is intended to be a cost-effective yet high quality illumination device.
Generally, an LED bulb includes a base, a circuit layer formed on the base, a plurality of LEDs arranged on the base and electrically connected with the circuit, an electrical connector and a driving circuit. The driving circuit has two wires with different polarities. The two wires of the driving circuit are electrically connected with an external power source by the electrical connector. However, it is needed to test the polarities of the wires at first. The steps for testing are complicated. Furthermore, after testing the polarities of the wires, the position of the driving circuit may be adjusted in assembly of the LED bulb; therefore, the positions of the wires which have been tested for their polarities beforehand may be required to be changed accordingly; such manipulation is time consuming and laborious, which results in a low assembling efficiency.
What is needed, therefore, is an LED bulb which overcomes the above-mentioned limitations.